Amplifying system



Jan. 26 1926. l 1,570,901

s. LOEWE y AMPLIFYING SYSTEM Filed March 19, 1921 Patented Jan. 26, 1926.

UNITED STATES 1,570,901 PATENT oFFlcE.

SIEGMUND LOEWE, OF BERLIN, GERMANY, ASSIGNOR T WESTERN ELECTRIC! COM- PANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

.YAMILII'YING SYSTEM.

Application led Iarch 19, 1,921. Serial No. 453,844.

To all whom it 'may concern.:

Be it known that I, SIEGMUND Lonwn, a citizen of the German Republic, residing at Berlin, Germany, have invented certain 5 new and useful Improvements in Ampliying Systems (for which I have filed application in Germany, July 8, 1919, L-48522), ot which the following is a full, clear, concise, and exact'description.

This invention relates to ampliiiers of the type employing space discharge devices hav-- ing an anode, a cathode, and a controlling grid. D The amplifiers which have previously been '15 used were constructed either for the ampli-Y fication of high frequency currents, or for .the amplification of low frequency impulses, but not for both.

The subject of the present inventionls a simple universal amplifier which by vlrtue of its'special construction is suited to the equally good ampliiication o any kind of electric impulse. High. frequency and low frequency amplifiers have prevlously been diierentiated because it is diicult to bring low frequency impulses eiectiyely to the amplifier without the interventlon of iron transformers; while, on the other hand, the presence o iron transformers makes' 1t 1m possible to bring high-frequency oscillations to the amplifier. But it is possible to'proportion a shunt with capacity, self lnduction, and resistance, such that this circuit forms a system whose impedance .is independent of the frequency. The shunt circuit consists o two branch circuits, one branch containing inductance and resistance, thus possessing inductive reactance, while the other branch contains capacity and re- 40 sistance, thus capacitative reactance. The conditions under which the 1mpedance of the shunt circuit is independent of the frequency are indicated by the iollowing equation where R, is the resistance of the inductive branch of the shunt circuit; Rz is the resistance of the capacitativ'e branch; L and C are the inductancerand capacity respectively of the two branches; and Z is the impedance of the combination. v

`high frequency System,

According to the invention such a system is used to lead the energy to the universal amplifier.

. The drawing shows the amplifier arranged 1n accordance with the invention.

1 and Zare two connecting terminals of the input circuit to which the impulses to be ampliied are .in some manner conducted. The network, or shunt 3, having an impedance which is constant, for oscillations of all frequencies impressed therea'cross, comprises one branch containing capacity 6, in series with resistance-8, and a second branch containing an inductahce element 7, containing inductance and fresistance in series. One end of this shunt circuit leads to the cathode,

.and the other to the electrostatic control element or grid of the first amplifier or repeater tube 4 of the space current type.

"Either an ohmic resistance 5 or a shunt similarV to shunt 3 can :be used for a coupling between the tubes in the cascade arrangement shown. It is important that the impedance or ohmic resistance of system 5 should be selectedequal or approximately equal to the internal resistance of tube 4; since only with this -condition can the best action be obtained, It will be noted that the grid of the second tube is conductively conected to the anode of the preceding tube.

'I'he other details of the figure are self-evident. There may be no special plate or anode battery, since the heating battery sufiices as is possible wth eilicient tubes. Anode batteries 9 may be used if desired: Ihe drawing shows only two tubes, although in practice a larger number may be used.

One further detail'should be mentioned: in case the last anode circuit is to contain a telephone receiver 10, it is advisable to so' construct the shunt of capacity, self induction, and resistance, that the telephone 10.

itself serves as the self-induction of this loop circuit.

The amplifier as described .by the prent invention can be directly inserted in any so that it acts as detector and makes .the incoming signals directly audible; for this reason it is especially suited to reception inwireless telephony.

Each tube then has a detecting and an ampl1.

fying action. The same ampliiercan also be used to advantage as a speech amplifier of the commen since it gives an ,unusu ally clear speech rendition in the absence of resonance to any of the speech frequencies. The whole system is veiy simple and cheap as the complicated intermediate transformers of the usual lowfrequency amplifier are avoided.

What is claimed is:

1. A repeater of the space current type,

having an 'electrostatic control element and l an input circuit, and a networlcincluding shunt elements only and containing reactance and resistance in series, connected to lsaid input.y circuit andhavinga substantially constar/it impedance for oscillations of kall frequencies impressed upon said input circuit.

' 2. A repeater of the space current type, having an electrostatic control element and an input circuit, and a network of shunt elements only, including inductance and resistance in series, said input circuit, said network having a substantially` constant iinpedance for oscillations of all frequencies capacity in series with resistance, in said input circuit, said means having a substantiall constant impedance forf oscillations of a l frequencies impressed upon said input circuit.

5. A,repeater of the space current type having an electrostatic control element and an .input circuit, and means, comprising a single closed loop including resistance, inductancc,`and capacity in series, connected in said input circuit, said loop having a substantially constant impedance for oscillations of all frequencies impressed upon said input circuit.

6. A repeater of thev space current type having an electrostatic control element and an input circuit, and a' network iii shunt to said input circuit comprising two parallel branch circuits, one of said branches containingl inductance and resistance, and the other of said branches containing capacity and resistance, said network having a substantially constant impedance for oscillations of all frequencies.

7. A repeater of the space current type having an electrostatic control element and an input circuit, and a network in shunt to said input circuit comprising two parallel branch circuits, one of said branches containing inductance,`L, and resistance, R1, and the other of said branches containing capacity, C and resistance, R2, said inductances, capacities and resistances having values as given by the equation 8. A repeater of the space current type, having an anode, a cathode, and a grid, and a network, containing shunt elements comprising reactances in series with resistances, connected between said cathode and said grid and having a substantially constant impedance for oscillations of all frequencies impressed between said grid and cathode.

9. A plurality of repeaters of the space current type connected in cascade, each of said repeaters comprising an anode, a cathfode, and a grid, the grid of one repeater being conductively connected to the anode of the preceding repeater, and means, containing reactances and resistances in series therewith, connecting said first named grid to its corresponding cathode and having a substantially constant impedance for oscillations of all frequencies impressed across said means, and a resistance connecting said second-named grid .to its corresponding cathode.

l0. A plurality of repeaters of the space cui-rent type connected in cascade, each of said repeaters comprising an anode, a cathode and a grid, the grid of one repeater being conductively connected to the anode of the preceding repeater, and a network connecting said last-named grid to its cor responding cathode comprising twoparallel branch circuits, one of said branches containing inductance, L, and resistance, R1,

Vand the other of said branches containing capacity, C, and resistance, R2, said inductaiices, capacities and resistances having values as given by the equation 1l. In combination, a vacuum tube detector for detecting and amplifying highl frequency waves, anoutput circuit there-v 12. An amplifier of the three-electrodey space current type, having an output circuit connected to an anode andi cathode and anv input circuit coiinectedto a `control electrode and said catlioc'i'ey?'andav network,

including a single' closed'lo'opffco taining reactaiice, connected in shunt -tojsa'iid'` input circuit, said network havinglsubsta'ntiallyiio constant impedance for all frequencies with- 1n the range mcludlng speech or radlo waves, and a resistance 1n sald output circuit of substantially the same impedance.

5 as the im edance of said tube between said anode an cathode.

13. In combination, a Vplurality of space/ discharge repeaters in tandem, input and output circuits for said repeaters, the input circuit of one repeater being connected to they output circuit of another repeater, and a network of substantially constant impedance for high and low frequency waves' included in the input circuit of one of said i5 repeaters, a similar network included in the output circuit of one of said repeaters, one v of said networks including the winding of a telephone receiver.

14. In an amplifier, a three-electrode space discharge tube, means connected to two'elec- 20 trodes of said tube having substantially constant impedance for high and low frequency waves, saidy means comprising an element including a capacity, and a second element in shunt to the firstelement including the l windings of a telephone receiver. In witness whereof, I hereunto subscribe my name this ninth day of February, A.

' DR.y SIEGMUND LOEWE. 

